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Diffstat (limited to 'include/net/mld.h')
| -rw-r--r-- | include/net/mld.h | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/include/net/mld.h b/include/net/mld.h new file mode 100644 index 000000000..23255cc47 --- /dev/null +++ b/include/net/mld.h @@ -0,0 +1,284 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef LINUX_MLD_H +#define LINUX_MLD_H + +#include <linux/in6.h> +#include <linux/icmpv6.h> + +/* MLDv1 Query/Report/Done */ +struct mld_msg { + struct icmp6hdr mld_hdr; + struct in6_addr mld_mca; +}; + +#define mld_type mld_hdr.icmp6_type +#define mld_code mld_hdr.icmp6_code +#define mld_cksum mld_hdr.icmp6_cksum +#define mld_maxdelay mld_hdr.icmp6_maxdelay +#define mld_reserved mld_hdr.icmp6_dataun.un_data16[1] + +/* Multicast Listener Discovery version 2 headers */ +/* MLDv2 Report */ +struct mld2_grec { + __u8 grec_type; + __u8 grec_auxwords; + __be16 grec_nsrcs; + struct in6_addr grec_mca; + struct in6_addr grec_src[]; +}; + +struct mld2_report { + struct icmp6hdr mld2r_hdr; + struct mld2_grec mld2r_grec[]; +}; + +#define mld2r_type mld2r_hdr.icmp6_type +#define mld2r_resv1 mld2r_hdr.icmp6_code +#define mld2r_cksum mld2r_hdr.icmp6_cksum +#define mld2r_resv2 mld2r_hdr.icmp6_dataun.un_data16[0] +#define mld2r_ngrec mld2r_hdr.icmp6_dataun.un_data16[1] + +/* MLDv2 Query */ +struct mld2_query { + struct icmp6hdr mld2q_hdr; + struct in6_addr mld2q_mca; +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u8 mld2q_qrv:3, + mld2q_suppress:1, + mld2q_resv2:4; +#elif defined(__BIG_ENDIAN_BITFIELD) + __u8 mld2q_resv2:4, + mld2q_suppress:1, + mld2q_qrv:3; +#else +#error "Please fix <asm/byteorder.h>" +#endif + __u8 mld2q_qqic; + __be16 mld2q_nsrcs; + struct in6_addr mld2q_srcs[]; +}; + +#define mld2q_type mld2q_hdr.icmp6_type +#define mld2q_code mld2q_hdr.icmp6_code +#define mld2q_cksum mld2q_hdr.icmp6_cksum +#define mld2q_mrc mld2q_hdr.icmp6_maxdelay +#define mld2q_resv1 mld2q_hdr.icmp6_dataun.un_data16[1] + +/* RFC3810, 5.1.3. Maximum Response Code: + * + * If Maximum Response Code >= 32768, Maximum Response Code represents a + * floating-point value as follows: + * + * 0 1 2 3 4 5 6 7 8 9 A B C D E F + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ +#define MLDV2_MRC_EXP(value) (((value) >> 12) & 0x0007) +#define MLDV2_MRC_MAN(value) ((value) & 0x0fff) + +/* RFC3810, 5.1.9. QQIC (Querier's Query Interval Code): + * + * If QQIC >= 128, QQIC represents a floating-point value as follows: + * + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + */ +#define MLDV2_QQIC_EXP(value) (((value) >> 4) & 0x07) +#define MLDV2_QQIC_MAN(value) ((value) & 0x0f) + +/* MLDv2 QQIC floating-point exponential field min threshold */ +#define MLD_QQIC_MIN_THRESHOLD 128 +/* MLDv2 QQIC FP max threshold (mant = 0xF, exp = 7) -> 31744 */ +#define MLD_QQIC_MAX_THRESHOLD 31744 +/* MLDv2 MRC floating-point exponential field min threshold */ +#define MLD_MRC_MIN_THRESHOLD 32768UL +/* MLDv2 MRC FP max threshold (mant = 0xFFF, exp = 7) -> 8387584 */ +#define MLD_MRC_MAX_THRESHOLD 8387584 +#define MLDV1_MRD_MAX_COMPAT (MLD_MRC_MIN_THRESHOLD - 1) + +#define MLD_MAX_QUEUE 8 +#define MLD_MAX_SKBS 32 + +/* V2 exponential field encoding */ + +/* + * Calculate Maximum Response Code from Maximum Response Delay + * + * MRC represents the 16-bit encoded form of Maximum Response Delay (MRD); + * once decoded, the resulting value is in milliseconds. + * + * RFC3810, 5.1.3. defines only the decoding formula: + * Maximum Response Delay = (mant | 0x1000) << (exp + 3) + * + * but does NOT define the encoding procedure. To derive exponent: + * + * For the 16-bit MRC, the "hidden bit" (0x1000) is left shifted by 12 to + * sit above the 12-bit mantissa. The RFC then shifts this entire block + * left by (exp + 3) to reconstruct the value. So, 'hidden bit' is the + * MSB which is shifted by (12 + exp + 3). + * + * Total left shift of the hidden bit = 12 + (exp + 3) = exp + 15. + * This is the MSB at the 0-based bit position: (exp + 15). + * Since fls() is 1-based, fls(value) - 1 = exp + 15. + * + * Therefore: + * exp = fls(value) - 16 + * mant = (value >> (exp + 3)) & 0x0FFF + * + * Final encoding formula: + * 0x8000 | (exp << 12) | mant + * + * Example (value = 1311744): + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0| 1311744 + * | ^-^--------mant---------^ ^...(exp+3)...^| exp=5 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * Encoded: + * 0x8000 | (5 << 12) | 0x404 = 0xD404 + */ +static inline u16 mldv2_mrc(unsigned long mrd) +{ + u16 mc_man, mc_exp; + + /* MRC < 32768 is literal */ + if (mrd < MLD_MRC_MIN_THRESHOLD) + return mrd; + + /* Saturate at max representable (mant = 0xFFF, exp = 7) -> 8387584 */ + if (mrd >= MLD_MRC_MAX_THRESHOLD) + return 0xFFFF; + + mc_exp = fls(mrd) - 16; + mc_man = (mrd >> (mc_exp + 3)) & 0x0FFF; + + return 0x8000 | (mc_exp << 12) | mc_man; +} + +/* + * Calculate Querier's Query Interval Code from Querier's Query Interval + * + * QQIC represents the 8-bit encoded form of Querier's Query Interval (QQI); + * once decoded, the resulting value is in seconds. + * + * RFC3810, 5.1.9. defines only the decoding formula: + * QQI = (mant | 0x10) << (exp + 3) + * + * but does NOT define the encoding procedure. To derive exponent: + * + * For any value of mantissa and exponent, the decoding formula indicates + * that the "hidden bit" (0x10) is shifted 4 bits left to sit above the + * 4-bit mantissa. The RFC again shifts this entire block left by (exp + 3) + * to reconstruct the value. So, 'hidden bit' is the MSB which is shifted + * by (4 + exp + 3). + * + * Total left shift of the 'hidden bit' = 4 + (exp + 3) = exp + 7. + * This is the MSB at the 0-based bit position: (exp + 7). + * Since fls() is 1-based, fls(value) - 1 = exp + 7. + * + * Therefore: + * exp = fls(value) - 8 + * mant = (value >> (exp + 3)) & 0x0F + * + * Final encoding formula: + * 0x80 | (exp << 4) | mant + * + * Example (value = 3200): + * 0 1 + * 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0| (value = 3200) + * | ^-^-mant^ ^..(exp+3)..^| exp = 4, mant = 9 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * Encoded: + * 0x80 | (4 << 4) | 9 = 0xC9 + */ +static inline u8 mldv2_qqic(unsigned long value) +{ + u8 mc_man, mc_exp; + + /* QQIC < 128 is literal */ + if (value < MLD_QQIC_MIN_THRESHOLD) + return value; + + /* Saturate at max representable (mant = 0xF, exp = 7) -> 31744 */ + if (value >= MLD_QQIC_MAX_THRESHOLD) + return 0xFF; + + mc_exp = fls(value) - 8; + mc_man = (value >> (mc_exp + 3)) & 0x0F; + + return 0x80 | (mc_exp << 4) | mc_man; +} + +/* V2 exponential field decoding */ + +/* Calculate Maximum Response Delay from Maximum Response Code + * + * RFC3810, relevant sections: + * - 5.1.3. Maximum Response Code defines the decoding formula: + * 0 1 2 3 4 5 6 7 8 9 A B C D E F + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * Maximum Response Delay = (mant | 0x1000) << (exp+3) + * - 9.3. Query Response Interval + * + * After decode, MRC represents the Maximum Response Delay (MRD) in + * units of milliseconds. + */ +static inline unsigned long mldv2_mrd(const struct mld2_query *mlh2) +{ + unsigned long mc_mrc = ntohs(mlh2->mld2q_mrc); + + if (mc_mrc < MLD_MRC_MIN_THRESHOLD) { + return mc_mrc; + } else { + unsigned long mc_man, mc_exp; + + mc_exp = MLDV2_MRC_EXP(mc_mrc); + mc_man = MLDV2_MRC_MAN(mc_mrc); + + return (mc_man | 0x1000) << (mc_exp + 3); + } +} + +/* Calculate Querier's Query Interval from Querier's Query Interval Code + * + * RFC3810, relevant sections: + * - 5.1.9. QQIC (Querier's Query Interval Code) defines the decoding formula: + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |1| exp | mant | + * +-+-+-+-+-+-+-+-+ + * QQI = (mant | 0x10) << (exp + 3) + * - 9.2. Query Interval + * - 9.12. Older Version Querier Present Timeout + * (the [Query Interval] in the last Query received) + * + * After decode, QQIC represents the Querier's Query Interval in units + * of seconds. + */ +static inline unsigned long mldv2_qqi(const struct mld2_query *mlh2) +{ + unsigned long qqic = mlh2->mld2q_qqic; + + if (qqic < MLD_QQIC_MIN_THRESHOLD) { + return qqic; + } else { + unsigned long mc_man, mc_exp; + + mc_exp = MLDV2_QQIC_EXP(qqic); + mc_man = MLDV2_QQIC_MAN(qqic); + + return (mc_man | 0x10) << (mc_exp + 3); + } +} + +#endif |